JP2014111418A - Travel control unit of electric automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travel control unit of an electric automobile capable of properly implementing gear ratio shift control and regenerative control of a motor when a vehicle is traveling downhill, sustaining a proper vehicle velocity suitable for a driver's sensibility, and improving fuel economy by fully collecting kinetic energy of the vehicle as generated electricity.SOLUTION: A driver's sense of danger derived from an increase in a vehicle velocity occurring when a vehicle 1 is traveling downhill is pre-set to any of ranks 1 to 4 in association with a jerk Sn (derivative of an acceleration) induced in the vehicle 1. A gear ratio stage of a transmission 5 and a regenerative torque of a motor 3 are designated in association with each of the ranks so that when the jerk Sn is high and the driver's sense of danger is high, a large braking force can act on the vehicle 1. When the vehicle 1 is traveling downhill, the rank is selected based on the jerk Sn, and the contents of control associated with the rank are implemented. Thus, an increase in the vehicle velocity V can be suppressed and the driver's sense of danger can be alleviated.

Description

  The present invention relates to a travel control device for an electric vehicle, and more particularly to a travel control device capable of accurately executing transmission shift control and motor regeneration control on a downhill road.

  For example, shift control of an engine vehicle using an engine as a driving power source is executed based on a target shift speed determined in advance from a shift map corresponding to the accelerator operation amount and the vehicle speed. However, the shift map does not take into account the running resistance of the vehicle due to road gradient or the like. For example, when the vehicle enters the downhill road and the driver's accelerator operation is stopped (accelerator operation amount = 0), The target gear position is uniquely determined according to the vehicle speed. For this reason, there is a problem in that downshifting cannot be performed even in a situation where downshifting is to be performed in order to suppress an increase in vehicle speed due to road surface gradient.

  As a countermeasure focusing on such a problem, for example, the technique of Patent Document 1 has been proposed. In the technique of Patent Document 1, three types of shift maps for a flat road, an uphill road, and a downhill road are set in advance, and the vehicle is traveling based on the difference between the predicted acceleration and the actual acceleration of the vehicle. A shift map corresponding to the road surface gradient is selected. Thus, for example, in a downhill slope shift map, it is possible to suppress the increase in vehicle speed on the downhill road by executing a downshift.

On the other hand, in recent years, hybrid vehicles equipped with an electric motor as a driving power source in addition to the engine have been put into practical use in order to improve the efficiency of conventional engine vehicles. In such a hybrid vehicle, for example, on a downhill road, regenerative braking force is generated by regenerative control of a motor to suppress an increase in vehicle speed, and the kinetic energy of the vehicle is collected as generated power and charged to a battery. Then, in a driving situation where the required torque increases in response to the driver's accelerator depression, such as an uphill road, the motor is powered by using the power charged in the battery, thereby reducing the burden on the engine and the vehicle Increases overall energy efficiency.
Therefore, it is conceivable to apply the shift control of Patent Document 1 to such a hybrid vehicle.

JP-A-5-71635

  By the way, since the running vehicle encounters downhill roads having various slopes, fine vehicle speed adjustment according to the road surface slope is required. For example, on a steep downhill road, the driver first stops the accelerator operation to suppress the increase in the vehicle speed, and performs the brake operation when the vehicle speed still increases. At this time, the driver determines whether or not the brake operation should be performed based on the increase / decrease state of the vehicle speed, but the driver is nervous. For this reason, it is desirable to suppress an increase in vehicle speed by automatic downshifting before the driver is forced to operate the brake.

However, according to the technique of Patent Document 1, although downshifting on a downhill road is possible based on a downhill road shift map, it is still possible to perform accurate shift control only to determine a target gear stage according to the vehicle speed. Couldn't hope. In addition, since it is not reflected in the shift stage until after the vehicle speed is changed, it is difficult to say that the control responsiveness is good.
On the other hand, in a hybrid vehicle, since the regenerative torque of the motor can be used as part of the braking force, it is also required to accurately control the regenerative torque in order to maintain an appropriate vehicle speed on the downhill road. However, since the driver's accelerator operation is stopped on the downhill as described above, in the conventional hybrid vehicle, the regenerative torque of the motor is only controlled according to the vehicle speed as in the shift control. As a result, the regenerative torque cannot be accurately and responsively controlled, and the regenerative torque of the motor cannot be effectively used to maintain an appropriate vehicle speed on the downhill road.

As described above, the conventional hybrid vehicle has inadequate gear shifting control and motor regenerative control on the downhill road and the response is not good, so it is not possible to realize appropriate vehicle speed control in accordance with the driver's sensitivity, There was still room for improvement in terms of driving feeling. In addition, this means that the kinetic energy of the vehicle obtained on the downhill road cannot be effectively collected as generated power, and it is difficult to say that the motor regenerative control is sufficiently utilized for improving fuel efficiency.
The present invention has been made to solve such problems, and the object of the present invention is to appropriately execute shift control and regenerative control of the motor when the vehicle travels on a downhill road, and thus the driver. It is an object of the present invention to provide a travel control device for an electric vehicle that can maintain an appropriate vehicle speed according to the above sensibility and can sufficiently improve the fuel consumption by sufficiently collecting the kinetic energy of the vehicle as generated power.

  In order to achieve the above object, the invention according to claim 1 travels by transmitting the power running torque generated by power running control of the motor to the drive wheel side through the transmission, and during running on the downhill road, In an electric vehicle in which regenerative control is performed and the regenerative electric power is charged into a battery, downhill traveling determination means for determining that the vehicle is traveling on a downhill road, and a differential value of acceleration of the vehicle is calculated while the vehicle is traveling When the travel on the downhill road is determined by the acceleration differential value calculation means and the downhill road travel determination means, the shift stage of the transmission increases as the acceleration differential value calculated by the acceleration differential value calculation means increases. And a control means for increasing the regenerative torque of the motor.

  According to a second aspect of the present invention, in the first aspect, the vehicle further includes an uphill traveling determination unit that determines that the vehicle is traveling on the uphill road, and the control unit determines whether the vehicle is traveling on the uphill road by the uphill road determination unit. As the acceleration differential value calculated by the acceleration differential value calculation means decreases, the gear position of the transmission is switched to the low gear side and the power running torque of the motor is increased.

As described above, according to the traveling control apparatus for an electric vehicle of the invention of claim 1, the differential value of acceleration is calculated while the vehicle is traveling, and the differential value of acceleration is calculated when the vehicle is traveling on a downhill road. As the value increases, the gear position of the transmission is switched to the low gear side to increase the regenerative torque of the motor.
Therefore, the braking force acting on the vehicle is adjusted in the increasing direction as the differential value of the acceleration generated in the vehicle increases while the vehicle is traveling on the downhill road, by switching the shift stage to the lower gear side or increasing the regenerative torque. For this reason, an increase in the vehicle speed caused by the downhill road can be automatically suppressed, a driver's sense of danger caused by an unintended increase in the vehicle speed can be alleviated, and fine control following the driver's sensitivity can be realized. In addition, the differential value of acceleration can improve the control responsiveness because it is an index reflecting the change in the vehicle speed from now on, and the kinetic energy of the vehicle obtained on the downhill road can be sufficiently collected as generated power to achieve improved fuel efficiency. it can.

According to the electric vehicle traveling control apparatus of the second aspect of the present invention, in addition to the first aspect, when the vehicle is traveling on an uphill road, the transmission stage of the transmission is lowered as the differential value of acceleration decreases. Switched to the gear side to increase the power running torque of the motor.
Accordingly, the driving force acting on the vehicle is adjusted in the increasing direction as the differential value of the acceleration generated in the vehicle decreases while the vehicle is traveling on the uphill road, by switching the gear to the low gear side or increasing the power running torque. For this reason, it is possible to automatically suppress a decrease in the vehicle speed caused by the uphill road, to relieve the driver's dissatisfaction due to the unintended decrease in the vehicle speed, and to realize fine control according to the sensitivity of the driver.

1 is an overall configuration diagram showing a hybrid truck on which a travel control device of an embodiment is mounted. It is a flowchart which shows the rank determination routine which vehicle ECU performs. It is a flowchart which shows the rank determination routine which vehicle ECU performs. It is explanatory drawing which shows the classification according to the jerk of a vehicle, and the control content corresponding to each rank.

Hereinafter, an embodiment in which the present invention is embodied in a travel control device for a hybrid truck will be described.
FIG. 1 is an overall configuration diagram showing a hybrid truck on which the travel control device of this embodiment is mounted.
The hybrid type truck 1 is configured as a so-called parallel type hybrid vehicle, and may be referred to as a vehicle in the following description. A vehicle 1 is equipped with a diesel engine (hereinafter referred to as an engine) 2 as a driving power source and a motor 3 that can also operate as a generator such as a permanent magnet synchronous motor. A clutch 4 is connected to the output shaft of the engine 1, and an input side of the automatic transmission 5 is connected to the clutch 4 via a rotating shaft of the motor 3. A differential device 7 is connected to the output side of the automatic transmission 5 via a propeller shaft 6, and left and right drive wheels 9 are connected to the differential device 7 via a drive shaft 8.

  The automatic transmission 5 is based on a general manual transmission and automates the engagement / disengagement operation of the clutch 4 and the switching operation of the shift speed. In this embodiment, the automatic transmission 5 has a forward speed 6-speed reverse-speed 1 speed. ing. Of course, the configuration of the transmission 5 is not limited to this, and can be arbitrarily changed. For example, the transmission 5 may be embodied as a manual transmission, or a so-called dual clutch automatic transmission having two power transmission systems. It may be embodied as a machine.

  A battery 11 is connected to the motor 3 via an inverter 10. The DC power stored in the battery 11 is converted into AC power by the inverter 10 and supplied to the motor 3 (power running control), and the driving force (power running torque) generated by the motor 3 is driven after being shifted by the automatic transmission 5. The vehicle 1 is traveled by being transmitted to the wheel 9. For example, when the vehicle 1 is decelerated, the motor 3 operates as a generator by reverse driving from the drive wheel 9 side (regenerative control). The negative driving force (regenerative torque) generated by the motor 3 is transmitted to the driving wheel 9 side as a braking force, and the AC power generated by the motor 3 is converted into DC power by the inverter 10 and charged to the battery 11. The

  The driving force generated by the motor 3 is transmitted to the driving wheel 9 regardless of the state of connection / disconnection of the clutch 4, and the driving force generated by the engine 2 is driven only when the clutch 4 is connected. 9 side. Therefore, when the clutch 4 is disengaged, the positive or negative driving force generated by the motor 3 as described above is transmitted to the driving wheel 9 side, and the vehicle 1 travels. When the clutch 4 is connected, the driving force of the engine 2 and the motor 3 is transmitted to the driving wheel 9 side, or only the driving force of the engine 2 is transmitted to the driving wheel side, so that the vehicle 1 travels.

The vehicle ECU 13 is a control circuit for integrated control of the entire vehicle. For this purpose, the vehicle ECU 13 includes an accelerator sensor 15 (downhill road judging means, uphill road judging means) for detecting the operation amount θacc of the accelerator pedal 14, a brake switch 17 for detecting the depression operation of the brake pedal 16, and the speed V of the vehicle 1. Various sensors and switches such as a vehicle speed sensor 18 for detecting the engine speed, an engine rotation speed sensor 19 for detecting the rotation speed Ne of the engine 2, and a motor rotation speed sensor 20 for detecting the rotation speed Nt of the motor 3 are connected.
The vehicle ECU 13 is connected with an actuator (not shown) for connecting / disconnecting the clutch 4 and an actuator for shifting the automatic transmission 5, and an engine ECU 22 for engine control and an inverter ECU 23 for inverter control. And a battery ECU 24 for managing the battery 11 are connected.

The vehicle ECU 13 calculates a required torque necessary for the vehicle 1 to travel based on the accelerator operation amount θacc by the driver, and selects the travel mode of the vehicle 1 based on the required torque, the SOC of the battery 11, and the like. In the present embodiment, an E / G mode that uses only the driving force of the engine 2, an EV mode that uses only the driving force of the motor 3, and an HEV mode that uses the driving force of the engine 2 and the motor 3 together are set as the travel mode. The vehicle ECU 13 selects one of the travel modes.
The vehicle ECU 13 converts the required torque into a torque command value to be output by the engine 2 or the motor 3 based on the selected travel mode. For example, in the HEV mode, the required torque is distributed to the engine 2 side and the motor 3 side, and torque command values for the engine 2 and the motor 3 are calculated based on the gear position at that time. In the E / G mode, the required torque is converted into a torque command value for the engine 2 based on the gear position, and in the EV mode, the required torque is converted into a torque command value for the motor 3 based on the gear speed.

  Then, the vehicle ECU 13 disconnects the clutch 4 in the EV mode and connects the clutch 4 in the E / G mode and HEV mode in order to execute the selected travel mode, and then sends a torque command value to the engine ECU 22 and the inverter ECU 23. Output as appropriate. Further, during traveling of the vehicle 1, the vehicle ECU 13 calculates a target gear position from a shift map (not shown) based on the accelerator operation amount θacc, the vehicle speed V, and the like, and the actuator 4 connects and disconnects the clutch 4 to achieve this target gear position. The operation and the shift operation of the shift stage of the transmission 5 are executed.

  On the other hand, the engine ECU 22 executes injection amount control and injection timing control so as to achieve the travel mode and torque command value input from the vehicle ECU 13. For example, in the E / G mode and the HEV mode, the driving force is generated in the engine 2 with respect to the positive torque command value, and the engine brake is generated with respect to the negative torque command value. In the EV mode, the engine 2 is stopped and held by stopping the fuel injection.

Further, the inverter ECU 23 drives and controls the inverter 10 so as to achieve the travel mode and the torque command value input from the vehicle ECU 13. For example, in the EV mode or HEV mode, the motor 3 is power-running for the positive torque command value to generate a positive driving force, and the motor 3 is power-running for the negative torque command value. Generate negative driving force. In the E / G mode, the driving force of the motor 3 is controlled to zero.
The battery ECU 24 detects the temperature of the battery 11, the voltage of the battery 11, the current flowing between the inverter 10 and the battery 11, obtains the SOC of the battery 11 from these detection results, and detects this SOC. At the same time, it is output to the vehicle ECU 13.

  Basically, the switching of the driving mode by the vehicle ECU 13 is switched to the HEV mode or the E / G mode in response to a request from the required torque or the battery SOC. For example, during traveling in the EV mode, when the required torque increases according to the accelerator operation and exceeds the output possible range of the motor 3, the mode is switched to the HEV mode, and the shortage of the motor driving force is compensated by the driving force of the engine 2. Further, during traveling in the HEV mode, when the required torque decreases in accordance with the accelerator operation and enters the output possible range of the motor 3, the mode is switched to the EV mode, and the engine 2 is stopped after the clutch 4 is disconnected. .

  By the way, as described in [Problems to be Solved by the Invention], when the shift control using the three types of shift maps described in Patent Document 1 is applied to the hybrid vehicle 1, The shift control of the transmission 5 and the regenerative control of the motor 3 are inadequate and the responsiveness is not good. For this reason, there has been a problem that appropriate vehicle speed control in accordance with the driver's sensibility cannot be realized and the regenerative control of the motor 3 cannot be fully utilized for improving fuel efficiency.

  Here, the inventor has focused on the jerk (the differential value of acceleration) of the vehicle 1 as an index that correlates with the sensitivity of the driver who is traveling the vehicle. For example, when driving a vehicle 1 having a manual transmission, the driver grasps a change in the running state of the vehicle 1 based on jerk, that is, a change in acceleration, and performs a shift operation based on the change. For example, on a steep downhill road, the acceleration suddenly changes in the increasing direction (the jerk is large), and the driver who senses this determines that the increase in the vehicle speed V should be suppressed and executes a downshift operation. Conversely, on a gentle downhill road, the increase in acceleration also becomes gentle (the jerk is small), so the driver determines that the suppression of the vehicle speed V is unnecessary and maintains the current stage (current shift stage).

The jerk, which is the twice differential value of the vehicle speed V, can be regarded as an index reflecting not only the current vehicle speed V but also the change in the vehicle speed in the future, and the driver unconsciously senses the jerk, and immediately changes the vehicle speed. The expected shifting operation is performed. Therefore, if the shift control is automatically executed based on the jerk, it is possible to realize the shift control that anticipates a change in the running state of the vehicle 1 in the future. As a result, not only the speed change control can always be performed accurately but also a change in the vehicle speed can be reflected in the speed change control promptly, thereby improving the control response.
The regenerative torque of the motor 3 is also the same. If regenerative control is executed based on jerk, regenerative control that anticipates the change in the running state of the vehicle 1 in the future, and thus regenerative control that is accurate and has good responsiveness. realizable.

Based on the above knowledge, in this embodiment, the shift control of the transmission 5 and the regenerative control of the motor 3 are executed based on jerk, and the details will be described below.
The vehicle ECU 13 executes a rank determination routine shown in FIGS. 2 and 3 at predetermined control intervals while the vehicle 1 is traveling. This routine ranks the driving state of the vehicle 1 and thus the driver's sensibility (risk and dissatisfaction described below) according to the jerk generated in the traveling vehicle 1. Then, as will be described later, control reflecting the driver's sensitivity is realized by appropriately changing the speed, changing the regenerative torque, or connecting / disconnecting the clutch 4 according to the rank.

More specifically, the ranking of the traveling state of the vehicle 1 is described. The driver traveling on the downhill road stops the accelerator operation, and determines whether the brake operation should be performed from the subsequent increase / decrease state of the vehicle speed V, thereby increasing the tension. It has been. The driver at this time is more nervous when the acceleration of the vehicle 1 is rapidly increasing due to the steeply descending slope, and feels the necessity to suppress the increase in the vehicle speed V due to the descending slope.
This driver's sensibility is defined as “danger” and, as will be described below, in order to reduce the driver's danger, the control content according to the four ranks corresponding to the danger and on the downhill road Shift control and regenerative control of the motor 3 are executed in a direction that suppresses an increase in the vehicle speed V. Each rank is divided into ranks 1 to 4 according to the sense of danger, with rank 1 being the most dangerous and rank 4 being the least dangerous.

In the present embodiment, control according to the rank classification of the running state is executed not only on the downhill road but also on the uphill road. The driver traveling on the uphill road is performing the accelerator operation, but nevertheless, the driver 1 feels frustrated as if the acceleration of the vehicle 1 is rapidly decreasing, and it is necessary to suppress the decrease in the vehicle speed V due to the uphill road. Feel. More specifically, the driver feels frustrated as the actual vehicle speed V increases or decreases with respect to the accelerator operation (the vehicle speed V increases slowly or the vehicle speed V decreases). It becomes easy.
At this time, the sensitivity of the driver is defined as “dissatisfaction”, and control according to the four ranks (ranks 6 to 9) corresponding to the dissatisfaction to relieve the dissatisfaction of the driver as described below. The shift control and the regeneration control of the motor 3 are executed in a direction that suppresses the decrease in the vehicle speed V on the uphill road. Each rank is divided into ranks 6 to 9 according to dissatisfaction, with rank 9 having the highest dissatisfaction and rank 6 having the lowest dissatisfaction.

ここに、Ｖnは今回の制御周期の車速、Ｖn-1は前回の制御周期の車速、Ｔsは制御周期である。

ここに、Ｄnは今回の制御周期の車両１の加速度、Ｄn-1は前回の制御周期の車両１の加速度である。 First, in step S2, the vehicle ECU 13 calculates the acceleration Dn of the current vehicle 1 according to the following equation (1), and further calculates the jerk Sn of the vehicle 1 from the acceleration Dn according to the following equation (2) (acceleration differential value calculation). means).

Here, Vn is the vehicle speed of the current control cycle, Vn-1 is the vehicle speed of the previous control cycle, and Ts is the control cycle.

Here, Dn is the acceleration of the vehicle 1 in the current control cycle, and Dn-1 is the acceleration of the vehicle 1 in the previous control cycle.

Therefore, based on the equation (2), the jerk Sn is calculated as a larger positive value as the acceleration of the vehicle 1 changes abruptly in the increasing direction, and the acceleration of the vehicle 1 changes abruptly in the decreasing direction. The jerk Sn is calculated as a larger negative value as the time is longer. Further, when the acceleration of the vehicle 1 does not change, the jerk Sn is calculated to a value of zero.
In order to perform ranking according to the sense of danger and dissatisfaction based on such jerk Sn, the first determination value S1 and the second determination value S2 are set in advance on the positive side and the first on the negative side. 3 determination value S3 and 4th determination value S4 are set (S1>S2>0>S3> S4), and each is memorize | stored in vehicle ECU13.

In the subsequent step S4, it is determined whether or not the rate of change Δθscc per unit time of the accelerator operation amount θacc is zero. When the determination is No, the process proceeds to step S6 to determine whether or not the accelerator operation amount θacc is 0, and when the determination is Yes, the process proceeds to step S8 (downhill road traveling determination means). At this time, the vehicle 1 is traveling on a downhill road, and it can be estimated that the motor 3 is under regenerative control.
In step S8, it is determined whether or not the jerk Sn exceeds the first determination value S1, and if the determination is Yes, it is determined whether or not the clutch 4 is connected in step S10. When the determination in step S10 is No, the routine is temporarily terminated. When the determination is Yes, it is determined in step S12 that the driver's danger is equivalent to rank 1, and based on the control content set in advance corresponding to rank 1. Shift control and regenerative control of the motor 3 are executed (control means).

FIG. 4 is an explanatory diagram showing rank classification according to the jerk Sn of the vehicle and control contents corresponding to each rank. At this time, the vehicle 1 is traveling on the downhill road in the HEV mode. As shown in FIG. 4, the regenerative braking force is generated by the regenerative control of the motor 3 in response to the accelerator off, and the engine brake is applied by the clutch 4 being connected. Is generated. In spite of these braking forces acting on the vehicle 1, the acceleration of the vehicle 1 increases rapidly due to, for example, a change in gradient when the vehicle moves from a gentle downhill to a steep downhill. (Sn> S1), the driver has a strong sense of danger in response to the sudden increase in unintended acceleration.
Therefore, it is necessary to relieve the driver's sense of danger and to automatically suppress the increase in the vehicle speed V before the driver performs the brake operation, and for this reason, an increase in braking force is required. Can be considered.

In rank 1, the gear position is switched to a gear position lower by one gear than the current gear position (shift down), and the regenerative torque of the motor 3 is increased by a predetermined correction amount. As the correction amount of the regenerative torque, three levels of large, medium and small are set in advance. In rank 1, the maximum correction amount is applied to the torque correction process. The braking force acting on the vehicle 1 increases due to the downshift and the increase in the regenerative torque, and the jerk Sn of the vehicle 1 gradually decreases.
If the determination in step S8 is No, the vehicle ECU 13 proceeds to step S14 to determine whether the jerk Sn exceeds the second determination value S2, and when the determination is Yes. In step S16, it is determined whether or not the clutch 4 is connected. When the determination in step S16 is No, the routine is temporarily terminated. When the determination is Yes, it is determined in step S18 that the sense of danger is equivalent to rank 2, and a preset control corresponding to rank 2 is executed (control means). ).

  At this time, the vehicle 1 is traveling on the downhill road in the HEV mode similarly to the rank 1. However, the increase in the acceleration of the vehicle 1 is more gradual than that of the rank 1 (S1 ≧ Sn> S2), for example, because the gradient change is not as steep as the rank 1 as in the transition from the middle descent to the steep descent. ). Therefore, it can be determined that the driver's sense of danger is lower than rank 1 and that the braking force required for suppressing the increase in vehicle speed is also lower than rank 1.

In response to such a demand for braking force, in rank 2, as shown in Table 1, the current gear stage is maintained without downshifting, and only the increase correction of the regenerative torque of the motor 3 is used. A medium correction amount is applied to the correction process.
Further, when the vehicle ECU 13 makes a determination of No in step S14, the vehicle ECU 13 proceeds to step S20 and determines whether or not the clutch 4 is connected. If the determination in step S20 is Yes, it is determined in step S22 that the sense of danger corresponds to rank 3, and control preset in correspondence with rank 3 is executed (control means).

At this time, the vehicle 1 is traveling on the downhill road in the HEV mode similarly to the ranks 1 and 2. However, the increase in the acceleration of the vehicle 1 is more gradual than that of rank 2 (S2 ≧ Sn> 0), for example, because the change in gradient is not as steep as in rank 2 as in the transition from gentle descent to medium descent. ). Therefore, it can be determined that the driver's sense of danger is even lower than rank 2 and that the braking force required to suppress the increase in vehicle speed is also lower than rank 2.
In response to such a demand for braking force, rank 3 is dealt with only by increasing the regenerative torque of motor 3 as in rank 2 as shown in Table 1, and the torque correction process has a minimum correction amount. Applied.

Further, when the vehicle ECU 13 determines that the clutch 4 is disengaged and makes a No determination in step S20, the vehicle ECU 13 determines in step S24 that the sense of danger corresponds to rank 4, and is set in advance corresponding to rank 4. The controlled control is executed (control means).
The vehicle 1 at this time is traveling in the EV mode, and the difference is that the engine brake is not applied due to the disconnection of the clutch 4. Then, the acceleration of the vehicle 1 increases more gradually than rank 3 (S2 ≧ Sn> 0), for example, when the gradient slightly increases in the gentle downhill region. For this reason, it can be determined that the driver's sense of danger is even lower than rank 3, and the braking force required to suppress the increase in vehicle speed is also lower than rank 3. In response to such a request for braking force, rank 4 responds with the same control as rank 3.

If the vehicle ECU 13 makes a determination of Yes in step S4, the vehicle ECU 13 proceeds to step S26 to determine whether or not the jerk Sn is 0. If the determination is No, the routine is terminated. If the determination in step S26 is Yes, it is determined in step S28 that the sense of danger corresponds to rank 5.
At this time, the vehicle 1 does not know the traveling mode or the gradient of the traveling road surface, but in any case, the acceleration of the vehicle 1 hardly changes (Sn = 0), and the accelerator operation amount θacc of the driver also changes little. Not done. This means that the driver does not feel the danger caused by the acceleration on the downhill road and the dissatisfaction caused by the decrease in the acceleration on the uphill road, and continues the current driving state. Can be judged appropriate. Therefore, in rank 5, as shown in Table 1, the current gear stage is maintained and the current regenerative torque of the motor 3 is maintained in order to continue the current vehicle state.

As described above, when the vehicle 1 is traveling on a downhill road, the braking force acting on the vehicle 1 by downshifting or increasing correction of the regenerative torque increases as the jerk Sn increases and the driver's sense of danger increases. Is adjusted in the increasing direction. For this reason, for example, if the jerk Sn of the vehicle 1 increases due to a gradient change during traveling on a downhill road, the braking force acting on the vehicle 1 is increased by switching to the high braking side rank (rank 1 side) accordingly. . As a result, the jerk Sn of the vehicle 1 begins to decrease, and accordingly the rank is sequentially switched to the low braking side (rank 4 side), and the braking force decreases.
As described above, on the downhill road, an appropriate braking force is always applied to the vehicle 1 according to the increase / decrease of the jerk Sn of the vehicle 1. For this reason, the increase in the vehicle speed V caused by the downhill road can be automatically suppressed before the driver performs the brake operation, and the driver's sense of danger caused by the increase in acceleration can be reduced. As a result, even on downhill roads, it is possible to realize fine gear shift control and regenerative control of the motor 3 according to the driver's sensitivity (risk) and maintain an appropriate vehicle speed V.

  In addition, since the jerk Sn reflecting the change in the vehicle speed from now on is used as an index, the shift control that anticipates the change in the running state of the vehicle 1 and the regeneration control of the motor 3, in other words, the control with good response can be realized. . For example, when the road surface gradient suddenly increases during traveling on a downhill road, it is necessary to increase the braking force quickly in order to suppress the increase in vehicle speed. By using the jerk Sn as an index, it is possible to rapidly increase the braking force by rapidly increasing the braking force on the premise that the vehicle speed V continues to increase rapidly for some time. By improving the control responsiveness as described above, the kinetic energy of the vehicle 1 obtained on the downhill road can be recovered as generated power without waste, and fuel efficiency can be improved.

  Further, in the setting of the control content in FIG. 4, when the regenerative torque of the motor 3 is increased in the order of ranks 4, 3, and 2 in accordance with the increase in the jerk Sn, and the increase in the jerk Sn cannot be suppressed, the rank 1 is set. A shift down has been added. In other words, power generation is performed by regenerative control of the motor 3 as much as possible using the kinetic energy of the vehicle 1 on the downhill road, and only when there is an insufficient amount of braking force, the shift is compensated. Therefore, the kinetic energy of the vehicle 1 can be recovered more efficiently as generated power.

  On the other hand, as is apparent from FIGS. 2 and 3, the processing of the vehicle ECU 13 calculates the jerk Sn of the vehicle 1, ranks the current driver's sensibilities, and sets the shifts corresponding to the ranks. It is only necessary to perform control and regeneration control of the motor 3, and therefore, it is only necessary to match the control contents according to each rank in the development stage. For example, the technique of Patent Document 1 that requires matching of three types of shift maps, etc. Compared with, development costs can be significantly reduced. As a result, the calculation processing load of the vehicle ECU 13 can be reduced, and the traveling state of the vehicle 1 on the downhill road or the uphill road can be quickly reflected in the control. For example, in a method that requires complicated calculation processing such as fuzzy control, the calculation time is prolonged and the control responsiveness deteriorates. However, such a problem can be prevented in advance.

  By the way, when the gradient change on the downhill road is very steep, it is possible that the increase in the jerk Sn of the vehicle 1 cannot be suppressed even if the downshift by rank 1 and the increase in regenerative torque are repeated. Therefore, in addition to the shift control and the regenerative control of the motor 3 as rank 1, in addition to the operation of existing braking means installed in the vehicle 1, such as an exhaust brake, a compression release brake of the engine 2, or a retarder, etc. Good.

Further, for example, when the jerk Sn exceeds S1 and rank 1 is selected, the shift control and the regenerative control of the motor 3 are dealt with initially, and when the state continues for a predetermined time, or the rank 1 control is repeated. When the shift speed reaches the minimum gear speed and the regenerative torque reaches the maximum value, the exhaust brake is sequentially controlled to the closed side. Nevertheless, when the jerk Sn does not decrease to rank 2, the compression release brake may be operated first, and then the retarder may be operated.
By such measures, the increase in the vehicle speed V caused by the downhill road can be more reliably suppressed by effectively using the existing equipment installed in the vehicle 1.

  On the other hand, when NO is determined in step S6 in FIG. 2 because the accelerator operation amount θacc is not 0, the process proceeds to step S30 in FIG. 3 (uphill road determination means). In step S30, it is determined whether or not the current motor torque is greater than or equal to 0, that is, on the power running side. If the determination in step S30 is Yes, the process proceeds to step S32. At this time, the vehicle 1 is traveling on an uphill road, and it can be estimated that the motor 3 is under power running control.

  In step S32, it is determined whether the jerk Sn of the vehicle 1 is less than 0 and greater than or equal to the third determination value S3. If the determination is Yes, it is determined in step S34 whether or not the clutch 4 is connected. If No, it is determined in step S36 whether or not the SOC of the battery 11 is greater than or equal to a predetermined determination value SOC0. When the determination is No, the routine is terminated. When the determination is Yes, the routine proceeds to step S38, where it is determined that the driver's dissatisfaction is equivalent to rank 6, and a preset control corresponding to rank 6 is executed (control means). ).

At this time, the vehicle 1 is traveling on the uphill road in the EV mode, and as shown in FIG. 4, a power running torque is generated by the power running control of the motor 3 according to the accelerator on, and the engine 2 is idled by the clutch 4 being disconnected. It is in the state of operation or shutdown. And although the power running torque of the motor 3 is acting on the vehicle 1, the acceleration of the vehicle 1 is changing in the decreasing direction, for example, for the reason that the gradient slightly increases in the gentle climbing slope region. (0> Sn ≧ S3).
Although the decrease in acceleration at this time is slight, the driver feels frustrated even if he receives an unintended decrease in acceleration, and feels somewhat dissatisfied. Therefore, it is necessary to alleviate the driver's dissatisfaction and to automatically suppress the decrease in the vehicle speed V. For this reason, it can be considered that the driving force needs to be increased.

  In rank 6, the power running torque of the motor 3 is increased by a predetermined correction amount. As the correction amount of the power running torque, three levels of large, medium, and small are set in advance. In rank 6, the minimum correction amount is applied to the torque correction process. As the power running torque increases, the driving force acting on the vehicle 1 increases, and the jerk Sn of the vehicle 1 gradually increases.

Further, when the vehicle ECU 13 determines Yes in step S34, the vehicle ECU 13 determines in step S40 that the dissatisfaction is equivalent to rank 7, and executes a preset control corresponding to rank 7 (control). means).
At this time, the vehicle 1 is traveling in the HEV mode on the uphill road, and the driving force of the engine 2 is acting on the vehicle 1 in addition to the power running torque of the motor 3, but the acceleration of the vehicle 1 is decreasing in spite of that. (0> Sn ≧ S3). Therefore, the driver has some dissatisfaction and is required to increase the driving force.
The control content of rank 7 is the same as that of rank 6, and the power running torque of the motor 3 is increased by the minimum correction amount.

  Further, when the vehicle ECU 13 makes a determination of No in step S32, the vehicle ECU 13 determines whether or not the jerk Sn is equal to or greater than the fourth determination value S4 in step S42. When the determination is Yes, it is determined at step S44 whether or not the clutch 4 is connected, and when the determination is No, the routine is terminated. Further, when the determination in step S44 is Yes, the process proceeds to step S46, where it is determined that the dissatisfaction is equivalent to rank 8, and the control set in advance corresponding to rank 8 is executed (control means).

At this time, the vehicle 1 is traveling on the uphill road in the HEV mode as in the case of rank 7. However, the acceleration of the vehicle 1 decreases more rapidly than rank 7 due to the fact that the gradient change is steeper than rank 7 as in the transition from gentle climbing to middle climbing slope (S3> Sn ≧ S4). . Therefore, it can be determined that the driver's dissatisfaction is higher than rank 7 and that the driving force required for suppressing the decrease in vehicle speed is also higher than rank 7.
In rank 8, the gear position is switched to the lower gear side than the current gear position (shift down), and the power running torque of the motor 3 is increased based on the medium correction amount.

  Further, when the vehicle ECU 13 makes a determination of No in step S42, the vehicle ECU 13 determines whether or not the clutch 4 is connected in step S48. If the determination is No, the routine is terminated. When the determination in step S48 is Yes, the process proceeds to step S50, where it is determined that the dissatisfaction is equivalent to rank 9, and the control preset in correspondence with rank 9 is executed (control means).

At this time, the vehicle 1 is traveling on the uphill road in the HEV mode as in the case of rank 7. However, the acceleration of the vehicle 1 decreases more rapidly than rank 7 due to the fact that the gradient change is steeper than rank 7 as in the transition from gentle climbing slope to steep climbing slope (S4> Sn). For this reason, it can be determined that the driver's dissatisfaction is higher than rank 8 and that the driving force required for suppressing the decrease in vehicle speed is also higher than rank 8.
In rank 9, the gear position is switched to the second gear position lower than the current gear position (skip shift down), and the power running torque of the motor 3 is increased based on the maximum correction amount.

  As described above, when the vehicle 1 is traveling on an uphill road, the driving force acting on the vehicle 1 by shifting down or increasing correction of the power running torque is increased as the jerk Sn is smaller and the driver's dissatisfaction is higher. Is adjusted in the increasing direction. For this reason, for example, when the jerk Sn of the vehicle 1 decreases due to a gradient change during traveling on an uphill road, the driving force acting on the vehicle 1 is increased by switching to the higher driving rank (rank 9 side) accordingly. . As a result, the jerk Sn of the vehicle 1 starts to increase, and accordingly the rank is sequentially switched to the low drive side (rank 6 side), and the driving force gradually decreases.

Thus, on the uphill road, an appropriate driving force is always applied to the vehicle 1 according to the increase or decrease of the jerk Sn of the vehicle 1. For this reason, since the increase of the vehicle speed V resulting from an uphill road is suppressed automatically and the driver's lack of accelerator operation is compensated, the dissatisfaction of the driver resulting from the fall of acceleration can be eased. As a result, it is possible to realize fine gear shift control and regenerative control of the motor 3 according to the driver's sensitivity (dissatisfaction) even on the uphill road, and to maintain an appropriate vehicle speed V.
In addition, by using the jerk Sn reflecting the change in the vehicle speed as an index, good control responsiveness can be realized on the uphill road as in the downhill road.

This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in the above-described embodiment, the present invention has been embodied in a hybrid truck equipped with the motor 3 as a driving power source in addition to the engine 1, but may be embodied in an electric vehicle equipped with only the motor 3, or may be applied to a bus or a passenger car. It may be embodied.
In the above-described embodiment, the jerk Sn (= danger, dissatisfaction) generated in the vehicle 1 on the downhill road and the uphill road is ranked, and the control content set in advance corresponding to the rank is executed. I made it. However, the present invention is not limited to this. For example, without ranking the jerk Sn, downshifting is performed when the jerk Sn exceeds a preset threshold on a downhill road, or the motor 3 is continuously regenerated as the jerk Sn increases. The torque may be corrected to increase. The same applies to the uphill road. Furthermore, the control based on the jerk Sn may be executed only on the downhill road without executing the control based on the jerk Sn on the uphill road.

3 Motor 5 Transmission 9 Drive Wheel 11 Battery 13 Vehicle ECU
(Downhill road running judging means, uphill road running judging means, acceleration differential value calculating means, control means)
15 Accelerator sensor (downhill road judging means, uphill road judging means)

Claims (2)

Electricity that travels by transmitting the power running torque generated by power running control of the motor to the drive wheel side through the transmission, and regeneratively controls the motor while driving downhill, and charges the battery with regenerative power In cars,
Downhill road traveling determination means for determining that the vehicle is traveling on a downhill road;
An acceleration differential value calculating means for calculating a differential value of acceleration of the vehicle while the vehicle is running;
When traveling on a downhill road is determined by the downhill road traveling determination means, the gear position of the transmission is shifted to the lower gear side as the acceleration differential value calculated by the acceleration differential value calculation means increases. And a control means for increasing the regenerative torque of the motor and switching the electric motor. An uphill traveling determination means for determining that the vehicle is traveling on an uphill road,
The control means has a gear position of the transmission that decreases as the differential value of acceleration calculated by the acceleration differential value calculation means decreases when traveling on the uphill road is determined by the uphill road determination means. 2. The travel control device for an electric vehicle according to claim 1, wherein the motor is switched to a low gear side and the power running torque of the motor is increased.

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